The present invention relates to a thermodynamic prime mover with a heat exchanger. More particularly, the invention relates to a gas turbine with a heat exchanger, which turbine is especially suitable for motor vehicles.
Prior art gas turbines comprise heat exchangers for supplying a portion of the heat contained in the exhaust gas, to the relatively cold compressed air in order to save fuel. It is this preheating of the compressed combustion air which makes possible an economical operation of a gas turbine, especially one that is employed as the prime mover in a motor vehicle.
However, the temperature of the air entering the combustion chamber of such gas turbines using heat exchange means in rather high, for example in the range from 700.degree. C and even higher. Where no heat exchange means are used in gas turbines the temperature of the air entering the combustion chamber is customarily in the range of 200.degree. C to 400.degree. C. It has been found that the preheated air, that is air having a temperature of 700.degree. C or more, does not have a sufficient cooling ability to adequately cool the flame pipe, which is conventionally made of sheet metal. As a result, the useful life of the flame pipe becomes rather short in gas turbines using heat exchange means whereby an economical operation again becomes questionable.
Attempts have been made heretofore to solve the above problem by providing complicated cooling slot configurations for the flame pipe. However, tests have shown that a satisfactory improvement in the cooling efficiency cannot be attained by means of such cooling slot configurations.